Merge branch 'aseitz/mips-got-ofst' into 'main'

Fix symbolic expression attributes for got_ofst

Closes #598

See merge request rewriting/ddisasm!1191

CHANGELOG.md

@@ -16,7 +16,8 @@
   constant address.
 * Refactor the code inference point system. Decouple heuristics from their weights.
   Heuristic weights can now be modified by providing user hints.
-
+* Generate GOT, PAGE and GOT, OFST symbolic expression attributes for split
+  .got loads on MIPS.
 
 # 1.8.0
 

examples/mips_asm_examples/ex_got_ofst/Makefile

@@ -0,0 +1,10 @@
+.PHONY: clean check
+out.txt: ex
+	@qemu-mips -L /usr/mips-linux-gnu $^ 2 > $@
+ex: ex_original.s
+	mips-linux-gnu-gcc -no-pie -o $@ $^ -lm
+clean:
+	rm -f ex out.txt ex.gtirb
+check: ex
+	qemu-mips -L /usr/mips-linux-gnu $^ 2 > /tmp/res.txt
+	@ diff out.txt /tmp/res.txt && echo TEST OK

examples/mips_asm_examples/ex_got_ofst/ex_original.s

@@ -0,0 +1,72 @@
+.set noreorder
+.set noat
+
+.text
+
+.global _start
+_start:
+    lui $gp,%hi(_gp)
+    addiu $gp,$gp,%lo(_gp)
+    move $ra,$zero
+    lw $a0,%got(main)($gp)
+    lw $a1,0($sp)
+    addiu $a2,$sp,4
+    addiu $at,$zero,-8
+    and $sp,$sp,$at
+    addiu $sp,$sp,-32
+    lw $a3,%got(__libc_csu_init)($gp)
+    lw $t0,%got(__libc_csu_fini)($gp)
+    sw $t0,16($sp)
+    sw $v0,20($sp)
+    sw $sp,24($sp)
+    lw $t9,%got(__libc_start_main)($gp)
+    jalr $t9
+    nop
+
+.globl main
+.type main, @function
+main:
+    addiu $sp,$sp,-32
+    sw $ra,28($sp)
+
+    lui $gp,%hi(_gp)
+    addiu $gp,$gp,%lo(_gp)
+
+    # call fun via got with split load
+    lw $t9,%got_page(fun)($gp)
+    addiu $t9,$t9,%got_ofst(fun)
+    jalr $t9
+    nop
+
+    move $v0, $zero
+
+    lw $ra,28($sp)
+    jr $ra
+    addiu $sp,$sp,32
+
+.globl fun
+.type fun, @function
+fun:
+    addiu $sp,$sp,-32
+    sw $ra,28($sp)
+
+    # puts("hello world")
+
+    lui $v0,%hi(message)
+    addiu $a0,$v0,%lo(message)
+
+    lui $gp,%hi(_gp)
+    addiu $gp,$gp,%lo(_gp)
+    lw $v0,%got(puts)($gp)
+    move $t9,$v0
+    jalr $t9
+    nop
+
+    lw $ra,28($sp)
+    addiu $sp,$sp,32
+    jr $ra
+    nop
+
+.section .rodata
+message:
+    .string "Hello world"

src/datalog/arch/mips_symbolization.dl

@@ -299,8 +299,8 @@ discarded_split_load(EA_hi,EA_lo,Dest_addr,Type,Points):-
 // e.g., lw v0, -32696(gp)  <-- v0: MIPS_BASE_ADDRESS
 //       addiu a0, v0, 2560 <-- 2560: offset from MIPS_BASE_ADDRESS to target L
 // ->
-//       lw v0, %got(L)(gp)
-//       addiu a0, v0, %lo(L)
+//       lw v0, %got_page(L)(gp)
+//       addiu a0, v0, %got_ofst(L)
 base_addr_offset_operand(EA,NextEA,Dest_addr):-
     gp_relative_operand(EA,1,_),
     value_reg(EA,Reg,_,"NONE",_,Value,_),
@@ -348,10 +348,12 @@ base_addr_offset_operand(EA,NextEA,Dest_addr):-
         Dest_addr >= Begin, Dest_addr <= End
     ).
 
-symbolic_operand_attribute(EA,1,"GOT"):-
+symbolic_operand_attribute(EA,1,"GOT"),
+symbolic_operand_attribute(EA,1,"PAGE"):-
     base_addr_offset_operand(EA,_,_).
 
-symbolic_operand_attribute(EA,2,"LO"):-
+symbolic_operand_attribute(EA,2,"GOT"),
+symbolic_operand_attribute(EA,2,"OFST"):-
     base_addr_offset_operand(_,EA,_).
 
 // Hi

src/passes/Disassembler.cpp

@@ -507,6 +507,7 @@ gtirb::SymAttributeSet buildSymbolicExpressionAttributes(
         {"TPOFF", gtirb::SymAttribute::TPOFF},
         {"DTPOFF", gtirb::SymAttribute::DTPOFF},
         {"NTPOFF", gtirb::SymAttribute::NTPOFF},
+        {"PAGE", gtirb::SymAttribute::PAGE},
         {"TLSGD", gtirb::SymAttribute::TLSGD},
         {"TLSLD", gtirb::SymAttribute::TLSLD},
         {"TLSLDM", gtirb::SymAttribute::TLSLDM},
@@ -519,6 +520,7 @@ gtirb::SymAttributeSet buildSymbolicExpressionAttributes(
         // MIPS
         {"HI", gtirb::SymAttribute::HI},
         {"LO", gtirb::SymAttribute::LO},
+        {"OFST", gtirb::SymAttribute::OFST},
         // X86
         {"INDNTPOFF", gtirb::SymAttribute::INDNTPOFF},
     };

tests/qemu-elf-mips32.yaml

@@ -5,7 +5,7 @@ default: &default
   binary: ex
 
   # Compilation configuration.
-  build:
+  build: &default-build
     c: ["mips-linux-gnu-gcc"]
     cpp: ["mips-linux-gnu-g++"]
     optimizations: ["-O0", "-O1", "-O2", "-O3", "-Os"]
@@ -27,6 +27,13 @@ default: &default
     cfg_checks:
       - dangling_auxdata
 
+assembly: &assembly
+  <<: *default
+  path: examples/mips_asm_examples
+  build: &assembly-build
+    <<: *default-build
+    optimizations: [""]
+
 test-strip-default: &test-strip-default
   test:
     wrapper: "qemu-mips -L /usr/mips-linux-gnu"
@@ -295,3 +302,6 @@ tests:
         compiler: "mips-linux-gnu-g++"
         flags: ["-no-pie"]
         skip: false
+
+  - name: ex_got_ofst
+    <<: *assembly